Pass an electric current through water and it breaks down into hydrogen and oxygen.

The process is called electrolysis and, when you move to a commercial scale, the reality is a bit more complex – particularly if you want to produce hydrogen at a low enough price to rival petrol.

ITM’s patented electrolyser technology uses polymer membranes, assembled in stacks, and can already beat the European Union’s target for 2015 by being able to produce a kilogramme of hydrogen – sufficient to transport you almost 60 miles in Hyundai’s ix35 Fuel Cell Electric Vehicle – for less than 10 Euro.

One of the key attractions of ITM’s technology is that you can use it to produce and store hydrogen as and when you want to.

It’s the perfect answer to wind power’s detractors who point out that the wind may not be there when you want it and you can’t easily store electricity produced by turbines when it isn’t needed.

The unreliability of the wind is one of the main reasons why electricity distributors won’t use it as part of the generating mix at times when demand is at its peak.

The other problem is that strong winds can produce more electricity than the grid knows what to do with.

Both lead to wind farms being taken off line and their turbines “parked” when they could be generating electricity.

In Denmark, that means that although the country has sufficient wind farm capacity to meet 20 per cent of its electricity needs, the best the Danes ever achieve is to supply about five per cent.

Meanwhile, in the UK, the Government paid out millions of pounds in compensation to wind farm owners last year when they had to switch off their turbines because the network could not cope with the excess power.

Using the excess electricity to produce hydrogen opens up a number of options that would keep the turbines spinning while ever there is a wind – and ITM Power either already has or is currently developing the technology for each of those possibilities.

The hydrogen can be stored and then recombined with oxygen from the air in fuel cells, which employ membrane technology similar to an electrolyser, but working in reverse to produce electricity and water as a by-product.

Hydrogen can be used to refuel vehicles, which either run on electric motors powered by fuel cells or, less efficiently, use hydrogen instead of petrol in a specially converted internal combustion engine.

Last, but not least, hydrogen can be injected into natural gas supplies in varying proportions, depending on the pressure of the supply – a solution that ITM is currently investigating in the UK and Germany.

The beauty of ITM’s technology is that it is transportable, scalable and can produce gaseous hydrogen under pressure at the flick of a switch.

Even with the best insulation, liquid hydrogen evaporates inside the tank and has to be vented to avoid dangerous pressure build up.

As a result, at the end of two weeks a tank that started out full of liquid hydrogen could have lost up to 60 per cent of the hydrogen that was originally inside.

In future we could all find ourselves filling up at fuel stations that never need to see another tanker – just as long as they are connected to a water supply, have a source of electricity that might even be their own wind turbine and a large metal box the size of a standard ocean container, emblazoned with the logo of Sheffield-based ITM Power on its side.